36 lines
1.6 KiB
Text
36 lines
1.6 KiB
Text
# sight.ludic - in the picture, within reach, and actually seen. A frustum says a subject is in FRONT
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# of the lens, not that the lens can see it: the ray walks the ground and the trunks between. It is
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# forgiving on purpose - the subject passes if its body or its head is clear.
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const PHT_STEP: float = 3.0 # metres between the ray's samples
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function pht_ray_point(x: float, y: float, z: float) -> bool {
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let cx = PhotoLens.x()
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let cy = PhotoLens.y()
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let cz = PhotoLens.z()
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let d = Math.sqrt((x - cx) * (x - cx) + (y - cy) * (y - cy) + (z - cz) * (z - cz))
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if d < 3.0 { return true }
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let n = int(Math.clamp(d / PHT_STEP, 6.0, 120.0))
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for s in 1 .. n {
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let f = float(s) / float(n)
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let px = Math.lerp(cx, x, f)
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let py = Math.lerp(cy, y, f)
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let pz = Math.lerp(cz, z, f)
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let g = PhotoLens.ground(px, pz)
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# the ground with 35 cm of slack; a trunk once past the lens's own few metres
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if g - 0.35 > py { return false }
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if d * f > 6.0 and py - g < 7.0 and PhotoLens.trunk(px, pz, 0.45) { return false }
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}
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return true
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}
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# is (x, y, z) in the picture, within `far`, and can the lens see it?
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export function photo_in_view(x: float, y: float, z: float, far: float) -> bool {
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let dx = x - PhotoLens.x()
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let dy = y - PhotoLens.y()
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let dz = z - PhotoLens.z()
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let d = Math.sqrt(dx * dx + dy * dy + dz * dz)
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if d > far or d < 0.5 { return false }
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if (dx * PhotoLens.fx() + dy * PhotoLens.fy() + dz * PhotoLens.fz()) / d < 0.72 { return false }
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if not PhotoLens.visible(x, y, z, 1.0) { return false }
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return pht_ray_point(x, y, z) or pht_ray_point(x, y + 0.55, z)
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}
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